US2880769A

US2880769A - Safety guard for saws

Info

Publication number: US2880769A
Application number: US666130A
Authority: US
Inventors: Platakis Peter
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-06-17
Filing date: 1957-06-17
Publication date: 1959-04-07
Anticipated expiration: 1976-04-07

Description

April 7, 1959 PLATAKIS 2,330,769

SAFETY GUARD FoR'sAws 'Filed June 1'7, 1957 I 2 Sheets-Sheet 1 INVENTOR. 4 PETERPLATAK/S HTTQBNE April 7, 1959 P. PLA'TAQKIS SAFETY GUARD FORSAWS Filed, June 17, .1957

2 Sheets-Sheet 2 INVENTOR.

u m 4 m. T f M m T P h R .w

United States Patent SAFETY GUARD FOR SAWS Peter Platakis, Minneapolis, Minn.

Application June 17, 1957, Serial No. 666,130

3 Claims. (Cl. 143-159) Various types of power saw guards have been proposed and utilized to perform two functions: first, to preclude accidental engagement of portions of an operators body or clothing with the highly dangerous blade itself; and, second, to prevent injury to the operatorfrom flying or kicked pieces of the material being sawed. Circular saws, both of the suspended blade type and the beneath the table type are particularly demanding of a suitable guard.

It is therefore an object of this invention to provide a guard primarly designed for use with circular saws and specifically of the suspended blade type, whereby the operator is protected from accidental engagement of body orclothes with the sawblade and is protected from inadvertent flying pieces, etc. I

Still a further object of this invention is' to provide a guard that may be installed on various saws with a minimum of modification and yet which will provide a maximum of safety. r v I 7 Still a further object of this invention is'to provide a saw guard of simple construction, inexpensive to manufacture and yet of high operational efiiciency anduse.

A furtherobject of this inventionresides in the provision of a: saw guard adapted to permit passage of material, particularly elongated material, in one direction, yet preclude passage of said material in a reverse direction.

Still a further object of this invention is to'provide' a new and useful saw guard having cooperating guard members, positioned one on-either side of the saw blade.

Still a further object of this invention is the provision of a unique saw guard in advance of the saw blade.

Still a further object of this invention is the provision ofa new and unique saw guard having a safety shield permitting viewing of the blade without impairing the operation of the saw.

Still a further object of the invention is to provide a saw guard for use in cooperation with a saw blade which may be swung with ease from a guard position to an inoperative position. I

Still a further object of this invention is to provide a saw guard comprising a safety shield and work retaining member operable in cooperation and whereby the safety shield may be retracted toout-of-the-way position separately or in unison with the work engaging member.

Still a further object of this invention is the provision of a new and unique saw guard which maybe utilized with equal efiiciency without regard to the angle at which the saw blade is set.

Yet a further object of this invention is to provide a saw guard of the aforementioned character which does not materially affect the normal operation and use of the saw yet provides protection for the operator. I 7

Other and further objects of the invention reside in the specific structural details of the guard itself, including the safety shield, the workengaging members, the positioning and provision of parallel work engaging members, one in front of the saw and one'behind the saw, the co- "ice 2 operation of the safety shield with one of the work engaging members, and means for retaining or permitting selective movement of the safety shield and front work engaging member to retracted position; and in other structural details thereof.

Other and further objects of the present invention are those inherent and apparent in the structure as described, pictured and claimed.

To the accomplishment of the foregoing and related ends, this invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various This invention will be described with reference to the drawings in which corresponding numerals refer to the. same parts and in which: Figure 1 is a modified vertical sectional view of a saw having a suspended circular blade and showing the in: vention in cooperation therewith. In this view the saw supporting structure is shown in phantom outline.

Figure 2 is a fragmentary plan view of the structure of Figure l. t

Figure 3 is a vertical sectional view taken along .the line and in the direction of the arrows 33 of Figure l and likewise showing the saw supporting structure in phan tom outline. Figure 4 (Sheet 1) is a fragmentary enlarged detail view of the means for retaining the safety shield or gate assembly in position. i

Figure 5 is a fragmentary partially sectional view ofthe means for retaining the front guard assembly in posiw tion; and

Figure 6 is a horizontal sectional view taken along and in the direction of the arrows 66 of Figure 5;

Throughout the specification and claims the invention will be described for the sake of reference in the position shown in the drawings. In this position the saw rotates in the direction of the arrow R inscribed thereon; the work or material is progressed in the direction of the arrow W; and a position to the right of the saw blade with reference to Figure l is described as in front of the saw, and a position to the left of the saw blade in Figure l as described to the rear or behind the saw.

This invention relates to guard structure of the type shown in Patent No. 2,263,128 and is an improvement thereover. The saw forms no part of this invention per se and hence will not be described in great detail. In the specific form illustrated it comprises a blade 11 suitably supported on a shaft or arbor 12 and driven by a motor 13 supplied by any suitable source of electricity. The motor 13 and blade 11 are supported by a column'14 on a cantilever supporting arm 15 in turn provided with a'column support 16 suitable secured to a table 20; The table as illustrated is provided with a plate member 21 having a transverse recess 23 in which the saw blade 11 is positioned, and is secured to suitable frame supporting means 24. The blade 11 is shown in vertical position but may be tilted forwardly or rearwardly out of the plane of the table in Figure 1 without voiding the safety provided by this invention.

To the table is bolted or otherwise secured a fence or work guide 25. As shown it is supported by a pair of angle brackets 26, each in turn bolted to the table section 21. The fence 25 may be of any suitable material, wood, metal, etc. and provides a straight edge or surface 30' against which the work M or material being sawed abuts and by which it is guided.

. The work M being cut orripped, is. traversed from'riglit to left with reference to Figure 1 or from in front of the blade 11 to the rear thereof in the direction of the arrow W. 'As seen, it comprises a single portion or board in the front of the saw (to the right, Figure 2) and two severed portions M1 and M2 at the rear thereof (to the left, Figure 2).

The front guard assembly 31 and a corresponding rear guard assembly 32 are supported upon brackets 33 having wing lugs 34 bolted to the rear surface 35 of guide 25 in longitudinally spaced relation. Each bracket 33 has a central boss 36, into which are threaded tubular

upright members

40 and 40A for supporting

assemblies

32 and 51, as shown in Figure 1. A T fitting 41 is secured to the upper end of member 40 for assembly 32 and has a horizontal bore receiving a rod 42 maintained in fixed position by a set screw 43, indicated in Figure 2.

Rod 42 may be solid or tubular and is provided with a threaded on or otherwise secured end cap or collar 44, which serves as a limit collar for sleeve 45.

Sleeves

45 and 46 are spaced on the rod 42 and serve as hinges for a depending guard member 51. A collar 50 is secured to the opposite end of rod 42 and cooperates with collar 44 to prevent relative axial movement of guard member 51 on rod 42. Hinges 45 and 46, as shown best in Figure 4, each comprises a strap member having parallel spaced

ends

52 and 53 and an enlarged arcuate portion 54. The arcuate portion 54 circumscribes the rod 42 and

ends

52 and 53 are bolted as shown in Figure 4 to the guard member 51.

Guard member 51 has a metallic work-engaging plate 55A secured to its lower end portion by bolts 56. The over-all height of guard member 51, including plate 55A, is relatively greater than the distance between the axis of rod 42 and the surface of Work table 21, whereby member 51 will assume the position shown in Figure 1, when a board M is moved into cutting engagement with saw The lower edge of work engaging plate 55A is serrated or toothed, as indicated in Figure 2, to prevent slippage of plate 55A on the surface of a board, should the saw teeth suddenly grip the board and tend to reverse its traveling movement relative to the saw. As illustrated, member 51 is of wood and member 52 of steel, and they are individual. However, it is to be understood that member 51 may be of other suitable material such as steel and member 55 may be integral therewith. In any event, member 55 comprises a plurality of teeth beveled as shown in Figure 1, the extension thereof permitting traverse of the work or material M in the direction of Figures 1 and 2, but precluding kick-back of either of the two severed portions M1 and M2 in a direction towards the operator. Thus, the work M may freely pass beneath the composite guard member (51 and 56), but cannot be retracted, as such movement of the work, usually a board, will cause the serrations or saw teeth at the bottom edge of plate 55 to dig into the surface of the board, as will be understood.

The front guard assembly 31 is provided with an upright tubular member or post 40A substantially identical to member 40 of the rear guard assembly 32. However, to member 40A there is welded or otherwise secured a collar or annular ring 60 providing a base on which a flanged member 61 may rotate. The uppermost end portion 62 of post 40A extends above the annular ring or plate 60 and serves to provide a pivoted support for the front guard assembly 31, as best shown in Figure 5.

Member 61 is provided at its lower end with an annular flange 63 and at its upper end with a laterally extend-' ing lug 64 to which is pivoted the bifurcated end 66 of a suitable handle 65. Handle 65 serves to lock member 61 against relative rotation on post 40A, as will subsequently be described. A horizontal member 42A, similar to member 42 of the rear guard assembly 32, is shown provided with a cap 44A, hinges 45A and 46A, guard 51A and plate 55A. Member 42A has one end threadedly secured in a laterally extending boss 70 of member 61. Frontguardassembly 31 operates in the same manner as the rear assembly 32 except, of course, it engages the work M before it has been sawed. Thus, because of being positioned in front of the saw blade, front guard 55 prevents return or retracting or kicking movement of the material M at that side of the blade, and front and

rear guard assemblies

31 and 32 thus cooperate to protect the operator from flying debris or splinters from both sides of the blade.

Each of the

collars

60 and 63 is provided with a cooperating channel or recess 71, as shown in Figures 5 and. 6 adapted to receive handle 65 to lock guard assembly 31 against relative rotation on post 40A. See Figure 6. Thus, when handle 65 is in the locked position of Figures 5 and 6, it will maintain the safety guard assembly 31 in the position of Figures 1, 2 and 3. When handle 65 is moved from the full to the dotted line position, as indicated in Figure 3, guard member 51A may be horizontally swung from the full to the dotted line position, as indicated in Figure 2, and thus be in retracted or out-ofthe-way position.

Means is also provided for protecting the upper portion of the operators body, and is shown comprising an upright safety shield, generally designated by the numeral 72, as best illustrated in Figures 1 and 3. To support shield 72, a tubular supporting member or upright 74 is shown threaded into the top end of member 61, and has a cap or end collar 75 secured to the upper end thereof. Collar 75 cooperates with a collar 76 positioned on post 74 adjacent to its lower end to prevent substantial vertical movement of safety shield assembly 72 thereon. Shield 72 comprises a suitable frame 77 having a transparent insert or window 78 therein, the frame 77 in this instance being of wood, and the window 78 of flexible plastic or glass and retained by nailed or screwed strips 80. A pair of hinges 81, similar to

hinges

45 and 46, serve pivotally to support the shield 72 on member 74, as will readily be understood by reference to the full and dotted lines in Figure 2. Suitable means such as hook 82 and eye 83 are provided, respectively, on shield 72 and guard member 51A, for securing the shield 72 in its raised inoperative position, indicated in dotted lines in Figure 1. When so positioned, safety shield 72 and guard member 51A may be simultaneously swung to an out-of-the-way position, as indicated by the dotted lines in Figure 2, member 51A then being supported in its raised position, as indicated in Figure 1.

The upright body protecting shield 72 may be moved to its inoperative dotted line position indicated in Figure 2, independently of the member 51A as will be appreciated, and in like manner, member 51A is movable independently of shield 72.

When the upright shield 72 is in its operative position as shown in Figure 1," it is retained in such position by a hook element 84 which, when in the full line position shown in Figure 4, secures shield 72 in its operative position. When hook element 84 is moved from the full to the dotted line position of that figure, shield 72 is released and may then be moved to its inoperative out-ofthe-way position, indicated in dotted lines in Figure 2.

During operation of the saw, the transversely disposed

guard members

51 and 51A are in constant engagement with the top surface of the board M, and will have no effect upon the sawing operation, so long as the board being sawed or ripped continues to advance through the saw head in a normal manner. However, should the saw blade suddenly grip the board or a loose splinter thereof and tend to kick it back in a direction towards the workman feeding the board through the saw,

guard members

51 and 51A will intercede or block such abnormal reverse movement of the board, or a part thereof, and thus prevent flying board to splinter thereof from striking and injuring the mechanic.

In like manner, should any loose splinters of the board be thrown upwardly in a' direction towards the upper portion or head of the operator, such flying splinters would be blocked by the upright shield 72. It will thus be seen that the present invention provides a safety guard for circular saws which positively protects the operator against being injured by flying splinters or boards, when ripping lumber with a circular saw such as herein disclosed.

The apparatus is extremely simple and inexpensive in construction, and is so designed that it may readily be applied to conventional saws now in commercial use by an unskilled mechanic or workman. Under normal working conditions, the bottom serrated edges of

guard members

51 and 51A rest upon and slide freely over the top surface of the board being fed through the saw, as shown in Figure 1. Thus

guard members

51 and 51A do not interfere with the normal free feeding movement of the board through the saw, but instantly become eifective to wedge the board firmly against the surface of the work table with a wedging action, should the saw suddenly tend to reverse the movement of the board as a result of the rapidly whirling saw teeth for some reason momentarily becoming caught or wedged in the saw cut or kerf.

Thus, it will be seen that the present invention provides a new and useful safety guard for saws comprising two independent assemblies, one positioned in front and one positioned behind the saw. The assembly positioned behind the saw has a work engaging member or means which precludes retracting or flying movement of pieces of the work after it is severed. The work engaging member or means positioned in front of the saw prevents similar movement of the work before it is severed regardless of the angle of blade 11. Upright shield 72 cooperates with the work engaging member 57 positioned in front of the saw to prevent rearwardly flying splinters from striking the operator. Guard member 51A may be moved to an elevated or out-of-the-way position with respect to the work table 21, as indicated in Figure 1, and the safety shield 72 may be individually moved to its retracted or out of the way position, as indicated by the dotted lines in Figure 2.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specific embodiments described are given by way of example only and the invention is limited only by the terms of the appended claims.

What is claimed:

1. A saw guard for use with a table saw machine, comprising an upright post positioned adjacent to one side of said table, a horizontal member mounted for pivotal movement on the upper end of said post and positionable over the travel path of the work, a work engaging member pivoted to said horizontal member and having its lower end positioned to engage the work before the work engages the saw and permitting free forward movement of the work, but precluding reverse movement of the work, the lower edge of said work engaging member being parallel to the work table and being of substantial width to assure adequate engagement with the work passing therebeneath to the saw, a safety shield positioned over said work engaging member and pivoted for swinging movement about the axis of said upright post, said work engaging member and safety shield being swingable about the vertical axis of said upright post independently of one another, means at the upper end of said post for locking said work engaging member against pivotal movement about the axis of said upright post, and means for locking said shield against horizontal swinging movement.

2. A saw guard according to claim 1, wherein said horizontal member has an enlarged head at one end for pivotally supporting it on said upright post, and said head has a latch thereon engageable with means on the upright post to secure the horizontal member against swinging movement thereon.

3. A saw guard according to claim 1, wherein the lower edge of said work engaging member has an elongated blade secured thereto, and the bottom edge of said blade comprising a plurality of saw-like teeth adapted to engage and bite into the work, should the work accidentally tend to reverse its movement.

References Cited in the file of this patent UNITED STATES PATENTS 404,233 Teeguarden May 28, 1889 697,565 Thomas Apr. 15, 1902 901,889 Cummings Oct. 20, 1908 2,257,459 Gardner Sept. 30, 1941 2,401,056 Dilley May 28, 1946 2,506,610 Mueller May 9, 1950 2,562,396 Schutz July 31, 1951 2,731,049 Akin Jan. 17, 1956